Portable media players are popular devices that play a variety of media. These players typically have a large database of media that is stored on the device. For example, a portable media player may contain a large music library with many song titles and artists. Depending on the extent of a user's music library, this large index (or list) of titles and names can number in the thousand to tens of thousands of items.
In order to reduce their size and retain portability, these players generally have a limited input mechanism with which a user can enter commands. A limited input mechanism generally means that the portable media player lacks a keyboard. Instead, these players have a small number of simple arrow keys that allow the user to input up, down, left, right, and accept commands. This simple type of limited input mechanism is also known as a directional pad (or d-pad). Other portable media players may have touch pads or touch screens that allow generally the same limited form of user input.
The combination of a large database and a limited input mechanism of portable media players often make it difficult for a user to find a desired item in the large database. This is especially true as the size of the user's database becomes increasingly larger. For example, as a user adds to her music library it may become increasingly more difficult to find a desired song or artist within that library using the limited input mechanism of the device.
In order to find a desired item, current portable media players generally use an infix matching technique. Infix matching techniques work by matching a sub-string (such as a partial song title or partial artist name) with character strings in the index of items. This matching of the sub-string occurs anywhere in the characters string. For example, if the sub-string to be matched contains the letters “ina,” then infix matching may find a match in the index of both “tina turner” and “christina.” Current portable media players also lack popularity matching, whereby the most popular items are matched before less popular items. For example, even though a particular user has a favorite song or artist it may require much input from the user on the limited input mechanism to obtain the desired favorite song or artist. This can be especially frustrating for the user when she desires a song or artist that is frequently played.
A user also may often use her portable media player to buy additional items from online sources to save in her player. For example, the user may want to buy additional songs to add to her music library from an online music store. In this situation, the number of items (such as song titles and music artists) contained in the index or database of the online store can easily number from several hundred thousand to millions. There are still other situations in which a user may want to buy items from a large index of items using a device having a limited input mechanism. For example, a user may want to buy an item (such as movies, cars, groceries, and so forth) from an online store using a cable television with input constrained by a limited input mechanism such as a television remote control. In these situations, the combination of a large database and limited input mechanism again make it difficult for a user to find a desired item in the large database.